Worm locking means for adjustable jaw wrench



p 22, 1959 c. w. COSLOW 2,905,037

WORM LOCKING MEANS FOR ADJUSTABLEVJAW WRENCH Filed Sept. 9, 1957 as s T f 11 24 22/38 1 I I 28 O ,Y- I I WA INVENTOR. CA/QL WC05LOW United States Patent WORM LOCKING MEANS FOR ADJUSTABLE JAW WRENCH Carl W. Coslow, Los Angeles, Calif., assignor to Pendleton Tool Industries, Inc., Los Angeles, Calif 21 corporation of California Application September 9, 1957, Serial No. 682,728

3 Claims. (Cl. 81-165) This invention relates to adjustable jaw wrenches and particularly to improved means for retaining the jaws of such wrenches in adjusted position.

Wrenches of the type under discussion comprise in the well known manner a handlemounting a fixed jaw and a movable jaw. Journalled for rotation on the handle and peripherally meshing with a series of rack teeth on the movable jaw is a worm. The arrangement of the wrenches is such that the movable jaw may be shifted toward and away from the fixed jaw to vary the jaw spacing by rotation of the worm in opposite directions.

In early wrenches of this character, the worm was free to rotate so as to be prone to accidental turningduring use of the wrench. Such turning of the worm, of course, upset the jaw setting.

In order to avoid this deficiency, various means have been devised for releasably locking the worm against accidental turning so as to assure retention of the wrench jaJWs in a desired setting.

A broad object of the present invention is the provision of an adjustable jaw wrench of the character .described embodying improved releasable lock means for restraining the jaw-adjusting worm. against-rotation.

A more specific object is the provision of an adjustable jaw wrench embody ng improved worm locking means of the character described, which means are automatically released in. response to a, predetermined torqueapplied to the worm in either. direction, so as to greatly simplify manual adjustment of the jaw spacing.

Further objects reside in the provision of an adjustable jaw wrench embodying improved worm. locking means. Of the character described, which means. are extremely simple in construction and capable of incorporation in the wrench with an absolue minimum number of additional manufacturing operations, and at only slight increase in cost over that required. to manufacture the basic wrench structure.

Other objects and advantages will become readilyapparent as the description proceeds. p

The above and other objects are achieved .in the illustrative embodiment of the present wrench by the pro vision of a series of interengaging, radiallyextending teeth on one end ofthe worm and the adjacent ,wall of the worm receiving opening in the'wrench handle frame. These teeth are yieldingly urged into meshing engagement by a compression spring acting between the handle frame and worm and act to restrain the latter against accidental turning. 1 l i i The teeth are generally V-shaped in transversefcrosssection. The inclination of the side faces of the teeth and the tension ofthe spring which retains the teethin meshing engagement are such that successive teeth on the. worm are automatically cammed out of engagement with the; teeth onlthe handle frame to permit the worm to turn in response to. a given torque applied to the latter in. either direction, the worm moving axially in onefdi motion and then the other through averyshortdistance 2,905,037 Patented Sept. .22, 1959.

as successive teeth on the worm pass the fixed teeth on the handle frame.

Thus, adjustment of the movable jaw of the wrench is simply accomplished by merely manually turning the worm in either direction. Audible clicks may be heard as the worm is rotated and its successive teeth ride over the fixed teeth on the handle frame. The worm is yieldingly held in adjusted position by the engagement of these teeth when not applied to the work. When applied to the work, the pressure on the movable jaw acts on the worm in a direction tomaintain the teeth forcibly engaged. Hence the worm remains in adjusted position under all conditions.

Manufacture of the wrench is greatly simplified by providing a raised annular shoulder on the worm in which the worm teeth may be formed by a simple stamping operation. Also, the handle is provided with only a pair of aligned radial teeth which extend transversely of the wrench handle so as to be capable of being readily formed on the handle by a simple broaching operation.

The invention may be best understood from the following detailed description taken in connection with the annexed drawings, wherein:

Figure 1 is a partial elevation of the present wrench;

Figure 2 is an enlarged showing of the area encircled by the arrow 2 in Figure 1;

Figure 3 is an enlarged section taken along line 33 of Figure 2;

Figure 4 is an enlarged showing of the area encircled by the arrow 4 in Figure 2;

Figure 5 is a partial bottom plan view of a worm; and

Figure 6 is a detail section taken on line 6--6 of Figure 3.

Referring now to these drawings, the illustrative wrench will be seento comprise a basic open end wrench structure including a handle 10 having an enlarged head 11, a fixed iaw12, and a movable jaw 14.. Fixed jaw 12 is, conventionally formed integral with the wrench head 11, as illustrated.

Movable jaw 14 is formed, in the well known manner, with an elongate tang 16 which is cylindrically or otherwise enlarged alongits. free edge. at 18. Tang 16 is slidably received 'in a complementary. slot 20 in the wrench head 11 for movement of .the movable jaw 14 toward and away from the fixed jaw 12.

This adjustment of the movable jaw is accomplished by rotation of a worm 22 which peripherallyjmeshes with a series of rack teeth 24 on the movable jaw tang 16. Worm 22 is disposed within a rectangular opening 26 in the wrench head 11 and is slidably journalled on a pin 28 which extends across the opening 26. Pin 28 is tightly but removably received at opposite ends in a bore 30 extending through the head to permit initial assembly of the wrench.

Formed on the lower end of the worm 22, as the wrench is viewed in Figure 2,.6oncentric with its turning axis, is a raised, annular shoulder 32. The outer diameter of this shoulder is somewhat less than the thickness of the wrench head 11 below the opening 26, as may be best observed in Figure 3.

Worm shoulder 32 has a series of radially extending, circumferentially spaced serrations 34 which define a series of V-shaped teeth 36. The provision of the raised shoulder 32 on the worm permits the serrations 34 and teeth 36 to be accurately formed by a simple and economical coining or stamping operation.

It is n'ecessary that a large. number of the teeth. be provided, and that the teeth be low, or short, for reasons that'wil'l appear presently. For example, for a typical .10" wrench, there. may be twenty teeth, of a height of Formed on the lower wall of the worm receiving we ice opening 26 are a pair of raised, V-shaped teeth 38. These teeth 38 extend in longitudinal alignment transversely of the plane of the opening 26 and radially with respect to the turning axis of the worm 22. This transverse extension of the teeth 38 permits the latter to be simply and economically formed by running a suitably configured broach through the opening 26.

During use of the wrench, engagement of the handle teeth 38 in the serrations 34 of the worm 22 restrains the latter against accidental turning so as to accomplish retention of a desired jaw setting. It will be seen that When the wrench is applied to the work, and a torque exerted thereby, the movable jaw of the wrench acts against the worm in a direction to hold the worm and frame teeth forcibly engaged, so that the worm cannot creep. The worm and frame teeth are normally yielding- 1y retained in meshing engagement by means of a compression spring 40 acting between the upper end of the worm and the upper wall of the wrench opening 26.

The upper end of the worm is formed with a circular pocket 42 for receiving thelower end of the spring. This permits the provision of only slight axial clearance between the ends of the worm and the adjacent walls of the opening 26, just sufficient to enable axial disengagement of the handle teeth 38 and worm serrations 34, while retaining sufiicient resiliency in the spring 40 to enable disengagement of the handle teeth and worm serrations. Such a relatively close axial fit of the worm 22 in its opening 26 is, of course, desirable to avoid excessive play in the wrench adjustment.

Referring to the enlarged detail of Figure 4, it will be observed that the side faces of the handle teeth 38 are inclined at an 80 angle relative to one another and at a 40 angle relative to a radial plane passing through the turning axis of the worm. The opposing side faces of adjacent worm teeth 36, defining the side walls of the worm serrations 34, on the other hand, are inclined at a 90 angle with respect to one another and at a 45 angle relative to a radial plane passing through the turning axis of the worm.

Clearance, as shown, therefore exists between the side faces of the handle teeth 38 and the side walls of the worm serrations 34 which assures proper seating of the teeth in the serrations. While such clearance is not absolutely necessary, it is desirable for the reason just stated. Thus, the teeth and serrations may, if desired, be made to complement one another.

It will be observed that when the worm is turned in either direction, the tips of the handle teeth 38 engage side walls of the worm serrations, which are inclined at a 45 angle with respect to the direction of relative turning movement between the teeth and side walls of the worm serrations. A camming force, exerted axially of the Worm, so as to act in a direction to disengage the handle teeth and worm serrations against the force of the spring 40, is thus exerted on the worm 22 when a torque is exerted on the latter in either direction.

The greater the restraining force exerted by the spring 40 on the worm, of course, the greater will be the torque which must be applied to the worm to effect release of the latter from the handle teeth. In the present Wrench, the spring 40 is so chosen that the value of the torque which must be applied to the worm to release the latter to adjust the jaw spacing is small enough to permit turning of the worm by one finger, as, for example, by the thumb of the hand holding the Wrench, and yet great enough to effectively prevent accidental turning of the worm while the wrench is being applied to the work.

It has been mentioned that release of the worm locking means to permit adjustment of the jaw spacing is eifected merely by turning the worm. In order to accomplish this action, i.e., camming of the handle teeth 38 and worm serrations 34 out of engagement by merely turmng the worm, the inclination of the side walls of the worm serrations tothe aforementioned radial plane must be greater than the critical or self-locking angle at which friction prevents the required camming action to take place. The illustrated 45 inclination of the side walls of the worm serrations is greater than such critical angle.

It has been mentioned hereinabove that it is necessary to the success of the wrench lock of the invention that a relatively large number of teeth or serrations be employed, e.'g., twenty for a ten inch wrench, and that the serrations be relatively short. The present instruction, in accordance with the invention, readily accommodates a large number of serrations, as twenty for a ten-inch V wrench, or more for a Wrench of larger scale; and the included angle of the wrench teeth, together with the illustrated rounding over of the crests of the teeth, results in very short teeth, e.g., .016" for the ten inch example chosen. It will be seen that with teeth of such shortness, the axial travel of the worm resulting from a tooth on the worm passing over a tooth on the wrench frame will be slight, and the corresponding travel of the movable jaw will be slight. It will be apparent that, in order to permit the wrench to be given a final close adjustment to the work, it is very important that this axial travel of the movable jaw for each passage of a worm tooth over a frame tooth be very slight, as has been accomplished. Further, a large number of teeth on the worm is also essential to obtainment of close or fine adjustability from the standpoint of a large number of stops or intervals per revolution of the worm. It will be seen that a twenty tooth worm provides eighteen stops per revolution of the Worm, :giving adequate fineness of adjustment.

It will be apparent, therefore, that there has. been described and illustrated a wrench which is fully capable of attaining the objects and advantages preliminarily set forth. While a preferred form of the Wrench has been illustrated, numerous modifications in design and arrangement of parts are possible within the scope of the following claims.

I claim:

1. An adjustable jaw wrench, comprising: a handle including a fixed jaw, a movable jaw including a rack supported on said handle for movement toward and away from said fixed jaw, a worm meshing with said rack, means supporting said worm on said handle for rotation and limited axial movement, rotation of said worm imparting movement to said movable jaw, interengageable teeth on the end of said worm remote from said fixed jaw and on said handle, a spring for axially urging said worm in the direction of the teeth on said handle to engage the latter teeth and the teeth on the worm and yieldingly lock said worm against rotation, said teeth being disengaged by opposite axial movement of the worm against the action of said spring, said teeth extending radially with respect to the turning axis of said worm and being of generally V-shaped cross-section so as to have inclined side faces which create a camming force on said worm in a direction to disengage said teeth when a torque is applied to the worm, the included angle between the side faces of the teeth on the worm being approximately 90 and the included angle between the side faces of the teeth on the handle being less than 90, whereby said teeth are disengaged to release said worm for turning to adjust the movable jaw by the axial camming force exerted on the teeth on the worm by the teeth on the handle when a torque is applied to said worm.

2. An adjustable jaw wrench, comprising: a handle including a fixed jaw, a movable jaw including a rack sup ported on said handle for movement toward and away from said fixed jaw, a worm meshing with said rack, said Worm having a raised, annular shoulder at its end remote from the fixed jaw, concentric with the turning axis of the worm, said shoulder being of relatively small radial-thickness and having a series of circumferentially spaced, radially extending teeth formed therein, teeth on said handle opposing and engageable with the teeth on said worm, and a spring for normally axially urging said worm in the direction of said teeth on the handle to engage the latter teeth with the teeth on the worm and lock the Worm against rotation, said teeth being dis engaged by opposite axial movement of the worm against the action of said spring, said teeth extending radially with respect to the turning axis of said worm and being of generally V-shaped cross-section so as to have inclined side faces which create a camming force on said worm in a direction to disengage said teeth when a torque is applied to the worm, said side faces being inclined to radial planes passing through said turning axis and bisecting the teeth by an angle which is greater than the critical angle at which said teeth self-lock against said camming force, whereby said worm is yieldingly restrained against accidental turning, and said teeth are disengaged to release said worm for turning to adjust the movable jaw by the axial camming force exerted on the teeth on the worm by the teeth on the handle when a torque is applied to said worm.

3. An adjustable jaw wrench, comprising: a body including a fixed jaw, a handle connected to said body, a movable jaw including a rack supported and guided on said body for movement toward and away from said fixed jaw, said body having an opening therein communicating with said rack, an axially movable worm in said opening meshing with said rack, said worm having a raised, annular shoulder at its end remote from the fixed jaw, concentric with the turning axis of the worm, said shoulder having a series of circumferentially spaced, radially extending teeth formed therein, teeth connected with said handle opposing and engageable with the teeth on said worm, and spring means acting axially on the worm for normally urging said worm teeth and said handle-connected teeth into i'nterengagement to releasably lock the worm against rotation, said teeth being disengageable to permit worm rotation by relative axial movement of the worm and said handle-connected teeth against the action of said spring means, said teeth extending radially with respect to the turning axis of said Worm and being of generally V-shaped cross-section so as to have inclined side faces which create an axial camming force between said worm and handle-connected teeth in a direction to disengage said teeth when a torque is applied to the worm, said side faces being inclined to radial planes passing through said turning axis and bisecting the teeth by an angle which is greater than the critical angle at which said teeth self-lock against said camming force, whereby said worm is yieldingly restrained against accidental turning, and said teeth are disengaged to release said Worm for turning to adjust the movable jaw by the axial camming force exerted between the teeth on the worm and the handle-connected teeth when a torque is applied to said worm.

References Cited in the file of this patent UNITED STATES PATENTS 1,148,410 Smith et al. July 27, 1915 1,498,656 Herby June 24, 1924 1,588,105 Hanford June 8, 1926 1,729,640 Vallone Oct. 1, 1929 r 1,954,914 Bouche Apr. 17, 1934 2,427,608 Kershaw Sept. 16, 1947 FOREIGN PATENTS 47,960 Sweden Nov, 24, 

